This invention relates to methods for the phototherapeutic treatment of illness and diseases.
Phototherapy is a promising clinical tool for the treatment for many conditions, including seasonal affective disorder, bulimia nervosa, herpes, psoriasis, sleep disorders, acne, and skin cancer.
Phototherapy is especially promising as a treatment for hyperbilirubinemia, a common condition affecting about 60% of all newborns. Hyperbilirubinemia is caused by the accumulation of excess bilirubin in the blood of the infant. This excess bilirubin turns the skin and sclera a characteristic yellow color. If left untreated, extreme cases of hyperbilirubinemia can result in neurological insult (kernicterus) or even death. A common treatment for hyperbilirubinemia is phototherapy, in which the infant is exposed to light in a range corresponding to the absorption spectra for bilirubin (blue-green, 400-550 nm). This light energy changes the form of the bilirubin to a different isomer that is more readily eliminated by the body.
Phototherapeutic light can be provided from above (by using an overhanging panel), from below (by using an illuminated pad or bed), from all sides (by using a phototherapeutic garment or blanket), or combinations thereof. Prior phototherapy systems are described, e.g., in Kremenchugsky U.S. Pat. No. 5,339,223; Rosen U.S. Pat. No. 6,045,575; Russell U.S. Pat. No. 6,290,713; Larsson U.S. Pat. No. 5,792,214; Nicholas U.S. Pat. No. 5,400,425; Vreman U.S. Pat. No. 6,596,016; Williams U.S. Pat. No. 6,872,220; Williams U.S. Pub. No. 2004/0039428; Bansal U.S. Pub. No. 2004/0068305; and Gardner U.S. Pub. No. 2006/0100675.
Regardless of the technique used, it is important to limit the “leakage” of phototherapeutic light; that is, phototherapeutic light not absorbed by the patient. Ideally, all the emitted light is absorbed by the patient, however a significant percentage of the phototherapeutic light never strikes the patient. This is especially true using overhanging panels and illuminated pads or beds. This leakage, or extraneous light, is simply wasted, and some individuals report nausea or discomfort from prolonged exposure to leaked phototherapeutic light. Systems and devices are therefore needed to reduce the amount of leaked or extraneous light during phototherapy.
In addition, phototherapy systems, particularly for infants, should be safe, effective and easy to use. For example, and extraneous heat generated a phototherapy system should be safely handled. Providing a comfortable and hygienic environment for the patient is also important.